If you were to have a given vehicle on a cold flat highway with good tyres at correct pressures your braking would be optimal. (mechanics.stackexchange.com)
I averaged less than 8 L / 100 km over a week of mixed city / highway driving and it dipped into the six range on a couple of flat highway stretches. (autofile.ca)
It's a good three - hour drive on a decent, flat highway from Cancun to Merida (or a one hour flight). (thebarefootnomad.com)